One-Nation One-Grid

Adequate generation and transmission facilities are available to meet the demand. Now the focus is towards ensuring 24x7 quality power supply and access of electricity to all at affordable price in an environmental friendly manner.

Indian Power System experienced phenomenal growth during the last few decades. Installed capacity has increased significantly from 170 GW during 2010 to 300 GW presently i.e., about 76 per cent increase. Towards this, private sector has contributed significantly, whose share has grown from 29 GW in 2010 to more than 115 GW in 2016, an increase of 296 per cent. In the past 5 years, penetration of renewable capacity has doubled, i.e. it has increased from 19 GW in 2010 to more than 40 GW in 2016. Peak and energy deficit has significantly come down to less than 2 per cent.

Role of Transmission Network
Towards meeting electricity demand of the country and also development of power system, transmission is playing a central role. Today, India has a transmission system comprising of about 24,245 circuit kilometre (ckm) of 765kV, 1,47,130 ckm of 400kV, and 1,57,238 ckm of 220kV level transmission lines.

HVDC bipolar links comprises 12,938 ckm and massive programme for enhancement of transmission capacity at an estimated investment of about Rs 2,00,000 crore are under way. In addition there is a massive network of sub-transmission and distribution network, supplying power to the end consumers. Such a large interconnected about 3,41,550 ckm long robust transmission network has facilitated seamless flow of power across the length and breadth of country.

Last five years have seen phenomenal growth in the development of transmission system network in the country. National grid capacity has been strengthened significantly through large scale addition of 765 kV Extra High Voltage (EHV) transmission Network. About 24,000 ckm of 765kV lines and more than 40 number of 765 kV substations has been added in past 5 years.

More than 40,000 ckm of 400 kV lines have also been added in past 5 years. Major Challenge in the development of transmission system is availability of Right of Way (RoW) for transmission lines and acquisition of land for establishment of substation.

Technology
Towards establishment of efficient, reliable and secure transmission system in the country, while addressing RoW & land acquisition issues, latest technologies viz., HVDC systems, GIS substations, FACTS devices like STATCOM, SVC etc. are being adopted on a large scale.

FACTS devices are installed in important AC transmission lines to increase the power transfer capacity. The hybrid mix of AC and DC transmission system in India has given the system operator to exercise a better control over the grid and flexibility in operation during any exigency in grid.

In the technology front, India has emerged as pioneer and is a world leader with the commissioning of 1,800 km of ¦800 kV multi-terminal HVDC system from Biswanath Chariali in North Eastern region to Agra in Northern Region and successful indigenous development 1,200 kV UHV AC system (highest Voltage in the world) which is under field trial since 2 to 3 years.

To cater bulk power transfer requirements, 11 nos. of high capacity power transmission corridors (HCPTCs) are being implemented in a phased manner matching with generation projects.

One Nation - One Grid
In the journey towards seamless flow of power across the region, on 31st December 2013, the Indian power sector achieved a major milestone when the Southern Regional Grid was successfully synchronized with the ´NEW´ grid (North, North East, East & West grids) through 765 kV Raichur-Solapur line.

With this milestone, the country now has only one synchronously connected grid in operation and long cherished dream of ´One Nation-One Grid´ has been fulfilled. Starting from five regional grids in early nineties we have today one national grid comprising more than 53,150 MW inter-regional capacity that would increase to 72,250 MW by the end of 13th plan period. At present, it is one of the very large power grids in the world having installed capacity of about 300 GW and meeting a peak demand of more than 150GW.

Asset Management
By adopting world class operation and maintenance practices and State-of-the-Art monitoring and control system at Load Dispatch Centers (RLDCs/NLDC) & National Transmission Asset Management Center (NTAMC), National Grid system is being maintained at high availability (more than 99 per cent) ensuring compliance with prescribed standards for uninterrupted supply of power to customers.

For dynamic stability monitoring & control, enhanced situational awareness etc., Load Dispatch Centers are equipped with synchrophasor measurement system. Under this Wide Area Measurement scheme about 63 Phasor Measurement Units (PMUs) have been installed at strategically selected locations across the country as a pilot project and world´s largest deployment of more than 1,700 PMUs at all inter-state and intra-state extra high voltage substations (400kV & above) have been undertaken as Unified Real Time Dynamic State Measurement system (URTDSM) project. Process Bus technology is being adopted at the substation to make it more efficient. Hot line maintenance, Helicopter based aerial patrolling using high resolution cameras, condition monitoring of equipment etc. have been adopted to ensure better reliability and availability of Transmission system.

Benefits of National Grid
Robust network of transmission system in the country has facilitated in harnessing the opportunities due to various types of diversity with respect to electricity production and consumption.

The strong and highly integrated transmission system has enabled development of a vibrant electricity market resulting in fall of electricity price from more than Rs 8 per unit in 2004 to less than Rs 3 per unit at present in power exchanges and provided momentum to the growth of the power sector as a whole.

Further, for the first time the spot market price of electricity on 29th Dec´15 was at a single price i.e. Rs 2.30 throughout the country, a great achievement for power sector. Thereafter, on several occasion single price has been witnessed in the power exchanges across the country.

It can be seen that stable and reliable transmission infrastructure of the country has brought competition in the sector, providing electricity at affordable price and also bringing efficiency into the sector. It has also facilitated in integration of renewable generation by increasing the grid size, to smoothly absorb variability and uncertainty associated with it.

Renewable Integration
The govenment has set an ambitious target of 175 GW renewable generation by 2022, which includes 100 GW of Solar, 60 GW of wind and 15MW other forms of RE generation. Out of 100 GW Solar, 20 GW would be through Solar parks, 40 GW through distributed solar generation and remaining 40 GW would be through rooftop solar generation.

Government has identified 34 solar parks in 21 states and EHV transmission system for evacuation of bulk power from these solar parks is also being developed as Inter-State/Intra-State transmission schemes. Renewable generation is highly intermittent, variable and uncertain in nature. Strongly interconnected transmission system present in India has played a vital role in integration of such a large scale of renewable generation.

It helps in transfer of power from surplus region to deficit region as well as sharing of balancing resources for dealing with intermittency and variability of Renewable generation.

To further facilitate in integration of upcoming large scale renewable generation, Green Energy Corridors are being developed.

that includes inter-state transmission system as well as intra-state transmission system. This also includes establishment of renewable energy management center for forecasting and scheduling of RE generation, dynamic compensation, load balancing, ramping, demand response, grid scale energy storage etc. There is no single technology or design, but this is a general term for the transformation of the power grid using digital communications and control to enable functionalities such as increased monitoring, resiliency, flexibility, efficiency, and intelligence.

Conclusion
With large scale integration of renewable generation, de-licensing of generation and growing electricity market, there is a paradigm shift in the way power system is being operated and maintained at present. On the one hand, to bring efficiency into the sector, various components of power supply value chain are operated at its limit and on the other hand, consumer demands reliable supply. In this context, a strong interconnected One-Nation-One-Grid spread over large geographical areas of non-uniformly distributed resources plays a vital role in facilitating transfer of bulk power from remotely located generating station to load centers.

After achieving the target of one nation-one grid, now efforts are being made to further strengthen the national grid, so that there is no bottleneck in the seamless flow of power across the country and we can have ´One Nation-One Grid-One Price´ in the country shortly.